ORIGINAL ARTICLE Antifungal activity of Carbendazim-conjugated silver nanoparticles against anthracnose disease caused by Colletotrichum gloeosporioides in mango Raghavendra Shivamogga Nagaraju 1 & Raghu Holalkere Sriram 1 & Rajeshwara Achur 1 Received: 13 November 2018 /Accepted: 22 July 2019 # Società Italiana di Patologia Vegetale (S.I.Pa.V.) 2019 Abstract Mango is one of the popular fruits in the tropical region including India and the production of this is adversely affected by Anthracnose disease caused by Colletotrichum gloeosporioides. This fungal infection during pre-and post-harvesting seasons causes significant economic loss and thus there is a need for effective fungicide to control the disease. Currently, many fungicides including Carbendazim at high concentrations are being used which is a serious environmental hazard. Recently, silver nano- particles (AgNPs) are being used as a potent means of controlling various pathogenic microorganisms. In this study, we have synthesized Carbendazim-conjugated silver nanoparticles (Cz-AgNPs) by a chemical method and tested their efficacy against C. gloeosporioides, in vitro. The Cz-AgNPs were characterized by UV-Visible, FTIR, SEM and XRD analysis. The shape of Cz- AgNPs was found to be spherical with an average particle size of 19–24 nm. The antifungal activity of Cz-AgNPs was found to be dose-dependent and the maximum potency was observed at a low concentration of 0.1% as compared to fungicide alone at 1% concentration. These results indicate that the Cz-AgNPs could be effectively used to control anthracnose disease in mango and in other crops as well. Further studies with other fungicides and field studies are in progress. Keywords Anthracnose disease . Colletotrichum gloeosporioides . Carbendazim . Silver nanoparticles Introduction Agricultural production has reduced worldwide over the past few years due to plant diseases. Millions of dollars have been invested in efforts to manage these plant diseases. Various natural and artificial methods including pesticide are employed for the control of these diseases. In recent years, environmental and health hazards caused by excessive use of pesticides have been widely discussed and thus there is a need for reducing the use of pesticides for the control of plant pathogens. A promising alternative in this direction is the use of silver nanoparticles as antimicrobial agents and the recent technological advances are even making their production more economical (Jo et al. 2009). Thus, there is a need for extensive research on fungicide conjugated silver nanoparticles which minimizes the use of fungicide while en- hancing the antifungal potency of silver nanoparticles. Mango (Mangifera indica L.) is considered as one of the most popular fruits in the tropical area and increasingly so in many countries including India. Mango fruits are very sensitive and subjected to decay under extreme environmental conditions in- cluding temperature and general fruit freshness is limited due to the rapid ripening, storage, handling and transportation damages. In addition to these limitations, Anthracnose disease caused by Colletotrichum gloeosporioides is the major postharvest disease of mango in all mango producing areas of the world (Dodd et al. 1989; Swart et al. 2002). The disease occurs as quiescent infec- tions on immature fruit and the caused damage is more important in the postharvest period (Muirhead and Gratitude 1986; Dodd et al. 1997). Fungicides, either as preharvest or postharvest treat- ments, form the main approach to reduce losses from anthracnose. Anthracnose disease was first identified in Chilly plant in 1890 (New Jersey, USA) by Halsted. The word ‘Anthracnose’ is derived from a Greek word meaning ‘coal’, which is the common name for plant disease characterized by very dark, sunken lesions, containing spores (Fig. 1). Generally, * Raghu Holalkere Sriram hsr1983@gmail.com 1 Department of Biochemistry, Kuvempu University, Shankarghatta, Karnataka 577451, India Journal of Plant Pathology https://doi.org/10.1007/s42161-019-00370-y